Biomolecules immobilized onto solid supports have great utility as affinity reagents, which are often utilized to bind and separate target molecules from mixtures. Oligonucleotides are one example of biomolecules which can be used for this purpose. For example, oligonucleotides can hybridize with complementary sequences. In addition, oligonucleotides having sequences found at regulatory regions can bind with regulatory proteins having specificity for those regions. Thus, affinity reagents comprising solid supports with immobilized oligonucleotides could be used inter alia in the purification, identification and isolation of complementary oligonucleotides and regulatory proteins.
Current methodologies for attaching oligonucleotides to solid phase supports have a number of shortcomings. For example, some methods result in non-specific attachment of the oligonucleotide or can cause side reactions. Methods which are specific typically involve attaching reactive groups directly to the 5′ or 3′ terminus of the oligonucleotide. Direct attachment at either terminus brings the oligonucleotide into close proximity with the solid support, which can prevent the oligonucleotide from adapting the proper configuration for binding with the target molecule. Other methods require significant manipulation of the matrix and oligonucleotide and are inconvenient to use.
Thus, there is a need for new methods of attaching oligonucleotides to the solid matrices which are convenient to use, site specific, result in minimal or no side reactions and which allow the oligonucleotide to adapt the proper orientation for binding with target molecules.